Nope! Eat until you are satisfied from any of these groups: fruits, vegetables, grains, legumes. Variety is good!

But do make sure it's a variety of groups, in addition to variety within groups. Get some of each but how much is up to what feels good to you. For example, if I start going heavier on grains and lighter on veggies (green leafies in particular) I tend to get heavier. We generally aim for dinner to be a bean, a green, and a grain - such as chickpeas, spinach, and quinoa in a casserole (one pot dinner since we pre-cook the beans: veggie stock to sweat some onion and garlic in a large saucepan with a lid, toss in the quinoa to toast a little and mix with the aromatics, add stock to cook the quinoa. once it's done, add the chickpeas and spinach and cover until the spinach is a little wilted and the chickpeas are warmed through). That makes a good dinner and also leftovers for next day lunch. Oatmeal for breakfast, leftover b-g-g for lunch, new b-g-g meal for dinner and that's 3-6 servings of grain just like that (depending on how much I eat of each thing). Add in a snack (hummus and multi grain/whole grain crackers for example) and there's another. Whole grains definitely help to make you feel full, which is good. A little goes a long way.